The seatbelt portion of a vehicle restraint system secures the occupant of a vehicle against harmful movement that may result from a vehicle collision. The seatbelt functions to reduce the likelihood of injury by reducing the force of occupant impacts with vehicle interior structures. In this role the seatbelt applies loads across the chest or lap of the occupant. The loads from the seatbelt may be increased by pretensioners that tighten the seatbelt upon detecting an impact occurrence or an incipient impact. Controlling or reducing these loads may reduce the risk of occupant injury during a collision.